Liquid metal micro switches (LIMMS) have been made that use a liquid metal, such as mercury, as the switching fluid. The liquid metal may make and break electrical contacts. To change the state of the switch, a force is applied to the switching fluid, which causes it to change form and move. If the adhesion between the electrical contacts and the substrate is poor, the moving switching fluid can sometimes lift the edges of the contacts and cause them to delaminate from the underlying substrate, damaging the switch.
Fluid-based switches are disclosed. In one embodiment, the switch comprises a first substrate and a second substrate mated together. Defined between the substrates are a number of cavites. Additionally, the first substrate defines a plurality of indentations within a first one of the cavities. A plurality of electrical contacts are each deposited within one of the indentations. Held within the first cavity is a switching fluid that serves to open and close at least a pair of the plurality of electrical contacts in response to forces that are applied to the switching fluid. The switch also includes an actuating fluid, held within one or more of the cavities, that applies the forces to the switching fluid.
In another embodiment, the switch comprises first and second substrates mated together so that a number of cavities are defined between the substrates. The first substrate additionally defines a plurality of indentations within a first one of the cavities. A plurality of wettable pads are each deposited within one of the indentations. Held within the first cavity is a switching fluid that is wettable to the pads. The switching fluid serves to open and block light paths through the first cavity in response to forces that are applied to the switching fluid. An actuating fluid, held within one or more of the cavities, applies the forces to the switching fluid.